Figure 2.

Biological solutions for landing, locomotion and take-off on highly irregular surfaces are diverse and depend on scale and flight adaptation. Powered flyers, shown in blue and teal colours, are able to use their wings to control their landing location with high precision while gliders, shown in purple and green colours, must land reliably at relatively higher velocities. Most animals pitch up to land on vertical surfaces, although bats are unusual in that they frequently invert to land upside-down. Larger animals predominantly use claws for attachment on vertical surfaces. Smaller animals typically use a combination of spines and adhesive pads. Frogs are unusual in that they typically land on leaves and stick to these smooth surfaces with wet adhesion. The flexibility of leaves dampens their impact. Flying snakes are also highly specialized and perch by wrapping their body around a landing branch. These animals all benefit from many joints that enable their bodies to adapt, comply and absorb energy upon landing. For take-off, most animals push-off from the surface with their legs or bodies. By contrast, bats usually hang upside-down and simply initiate their flight by dropping. (Animal drawings: Margarethe Roderick.)